Analytical and Experimental Investigations on Influential Parameters of Superplastic Forming of Titanium Based Workpieces

Superplastic fonning is a viable method for shaping supperallosis including titanium based materials which are otherwise awkward to shape. Further effort is, however, required to commercialize this process and introduce it to metal forming enterprises. Special facilities capable of providing controllable forming environment are needed for implementing this process. A hot isostatic/isothermal pressing machine possessing such a characteristic is an effective candidate for this purpose. Hot isostatic pressing has vastly been employed for diffusion bonding, powder metallurgy and investment casting, while its application to bulk- and sheet-metal forming needs far more investigation. Careful selection of processing parameters such as gas pressure, strain rate, temperature and process time is vitally important for superplastic forming of titanium based uiorkpieces. In an attempt to advance the superplasiic forming technology towards achieving a feasible process, the authors developed a low price hot isothermal pressing device with the aid of which numerous forming experiments were carried out. An additional objective pursued by the authors was to elaborate on the analytical method superplasiic forming of lens-shaped components which have considerable industrial applications and to illustrate the close relation between the analytical results and the experimental achievements.